Ugetsu is a legendary fisherman who is often spoken of in the Island Nations. He is an acquaintance of Shiramine, and accidentally fished him up when he was working on Lazlo's ship in the Island Liberation War. The two started working together again on the ship until the end of the war, when Ugetsu returned to Na-Nal to continue his quiet life at the pier. - KoRnholio

Gameplay Information for Suikoden IV

How to Recruit: After your headquarters is launched into the sea, return to Na-Nal and speak with him beside the trading shop.
Note: Ugetsu appears randomly. Repeatedly leave Na-Nal and return until he shows up. He seems to appear automatically after recruiting Rita.